Crankshaft grinding device



Feb. l, 1955 E. A. FUGLIE 2,700,851

CRNKSHAFT GRINDING DEVICE Filed July 31, 195s HTTORNEJS United States Patent O CRANKSHAFT GRINDING DEVICE Elmer A. Fuglie, Winona, Minn., assigner to Winona Tool Manufacturing Company, a partnership Application July 31, 1953, Serial No. 371,536

3 Claims. (Cl. 51-166) The present invention relates to improvements in the construction and support of the grinding wheel used in a crankshaft grinding device. In particular it relates to an improvement in the construction of the grinding wheel so as to obtain a more prolonged usage of the bonded abrasive stone, but more particularly it is concerned with properly supporting the abrasive stone with respect to a crankshaft grinding device, so as to reduce vibration of the grinding wheel and thus increase the accuracy of the grinding operation.

Having reference to my prior patents, 2,130,003; 2,247,344; 2,298,005; 2,391,406; and 2,629,213, all re lating to crankshaft grinding devices, the grinding element consists of a cylindrical shaped stone composed of bonded abrasive having axial openings at each end which extend into the stone but are not interconnected. A relatively slender drive shaft is threaded into one of these axial openings and extends into the stone for a substantial distance to securely hold the stone on the outer end of the shaft. The drive shaft is itself supported at a distance from the stone by a tubular bushing that is housed within a tubular support forming a part of the crankshaft grinding device. This latter device, as shown in my prior patents, is generally mounted on an internal combustion engine, either above or beneath the crankshaft and is supported in such a manner as to have a portion thereof reciprocate with the crankshaft bearing when the crankshaft is slowly rotated to cylindrically grind the crank pins or bearings that support the crank arms. The grinding operation occurs between the outer end of the bonded abrasive stone and the bearing of the crankshaft.

Based on an extensive experience with crankshaft grinders, I am aware of the fact that because of the nature of the connection between the drive shaft and the bonded abrasive stone which is mounted on the drive shaft, that only a limited amount of the stone can be successfully used because heretofore the drive shaft has extended into the stone for a substantial distance in order to rmly secure the stone on the shaft. From this I have concluded that a greater proportion of the stone could be used for grinding purposes if a broader shallower connection could be made between the shaft and the stone, but which would be sufficiently strong to properly support the stone on the shaft. Aside from the economic advantage which could be gained through a more extensive use of the stone, I have been aware of the fact that prior stone mountings have been ineicient in that they permit a certain amount of lateral vibration of the stone. This vibration results from the stone being mounted on the outer or free end of the drive shaft which lacks suitable bearing support from the housing of the crankshaft grinding device.

In the present invention l have provided an improved mounting for the stone which eliminates vibration and also allows a substantially greater amount of the stone to be used for grinding purposes. This is accomplished by providing a relatively broad, shallow opening in the base of the stone, in which is permanently mounted a relatively broad internally threaded annular member. The drive shaft which supports the stone is formed with an enlarged head which is externally threaded to lit within the annular member. The head of the drive shaft is itself provided with an annular recess about the outer end of the shaft to receive one end of a bushing whose other end is held within a supporting housing of the grinding device. By this arrangement a complete bear- 2,700,851 Patented Feb. 1, 1955 ing surface is provided for the drive shaft which extends into the interior of the stone and thus eliminates vibration of the stone. The bushing also provides an added bearing surface for the stone to give smoother operation. When it is considered that the grinding stone moves between oppositely disposed shoulders of the bearing or crank pin, elimination of vibration is important as otherwise the lateral cylindrical surface of the stone is brought into contact with the bearing shoulders and performs a grinding operation that is not only unnecessary, but undesirable since it may likely increase the total width of the crangshaft bearing.

An object of the invention is to provide an improved mounting for a bonded abrasive stone of a crankshaft grinder to reduce vibration of the stone and provide for the use of a larger amount of material forming the stone.

Another object is to provide in a crankshaft grinder a mounting for the stone which accommodates one end of a bushing that surrounds the drive shaft so as to provide an extended bearing surface for the shaft and a bearing surface for the stone.

A further object is to provide in a crankshaft grinder embodying a support, a driven shaft extending from the support, a bushing surrounding the shaft, of a stone mounting on the end of the shaft formed with an annular recess about the outer end of the shaft to receive a portlon of the bushing so that the drive shaft is supported throughout its entire length, and a bearing surface is provided between the end of the shaft and the stone to eliminate vibration of the outer end of the shaft that supports the stone.

Other and further objects may become apparent from the following description and claims, and in the appended drawings in which:

Fig. l is a side elevation of a fragmentary portion of a crankshaft grinder, showing the improvements in the stone mounting that forms the present invention;

Fig. 2 is a vertical section through the grinding stone and drive shaft shown in Fig. l;

Fig. 3 is a top plan view of the stone shown in Fig. 2;

Fig. 4 is a bottom plan view of the stone and shaft and mounting shown in Fig. 2; and,

Fig. 5 is a vertical section of the drive shaft with the improved head thereon.

Referring now to the several views of the drawing, the invention will be described in detail.

Referring first to Fig. 1, general reference numeral 10 indicates a fragmentary portion of a crankshaft grinder such as is shown in greater detail in my prior Patents 2,247,344 and 2,298,005. These devices are provided for grinding the crank pins on the crankshaft of an internal combustion engine without necessarily removing the crankshaft from the engine. Reference numeral 12 indicates a fragmentary portion of a shaft whose upper end, not shown, supports a yoke that embraces a portion of the crank pin. Reference character 14 indicates a conventional bushing that surrounds rod 12. Surrounding bushing 14 and extending laterally therefrom is an arm structure 16 which supports the grinder assembly, indicated by general reference nu meral 18 and which is shown in greater detail in the remaining figures of the drawing.

Referring now to Fig. 2, the grinder assembly 18 is shown in section. It consists of a cylindrically shaped stone 20 formed of bonded abrasive. Within the upper end of stone 20 and extending axially therein is a cylindrical opening 22 which is closed at its inner end. Within the interior of the bottom end of the stone is a large shallow cylindrical opening 26 that is separated from opening 22 by a partition 24.

Within the interior of the lower opening 26 is an annular member 28 that is relatively broad and shallow and which is interiorly threaded, as indicated at 30. The annular member 28 is firmly held within the recess 26 and in ordinary practice this firm bond is obtained by the use of molten sulfur, not shown, which is put into the recess before the annular member 28 is inserted therein, and which on cooling expands to form a permanent ggnd between the stone and the metal forming member As best seen in Fig. 5, a drive shaft 32 is formed with an enlarged head 34 which may be either integral with the shaft or preformed and secured on the outer end of the shaft. Member 34 is provided with a threaded lateral surface 36 to tit within the threaded surface 30 of member 28. On its interior, member 34 is formed with an annular recess 38 surrounding the outer end of shaft 32 and extending up into member 34 for a substantial distance. A bushing 40 which is of tubular contour surrounds shaft 32 and extends into the annular recess 38, as can be clearly seen in Fig. 2, to provide a bearing surface between the head portion 34 and all parts carried by said portion and the shaft 32.

As is clearly seen in Fig. 1, bushing 40 extends into a bearing surface 42 of the arm structure 16 and thus provides a first bearing surface 44 with bearing 42, and a second bearing surface, shown in Fig. 2 and designated at 46 with the head portion 34 of the drive shaft 32. It will be evident that bushing 40 may be of any length and that the grinding stone 20 need not be closely related to the arm structure 16, as shown in Fig. l, because bushing 40 forms the double bearing surfaces 44 and 46 between the grinding device 10 and the grinding stone 20. It will also be evident that by virtue of the broad, shallow connection between the outer end of the drive shaft 32 and the stone 20 that the stone may be used throughout substantially two-thirds of its length, which is a material increase in the usable portion of the stone over prior art crankshaft grinders.

While some economic advantage is gained through the i stone mounting by providing for a greater usage of the stone, the principal advantage of my invention resides in providing a bearing surface for the stone through the novel mounting which eliminates vibration of the outer end of the drive shaft, thus eliminating lateral movei' ment of the stone.

My invention is defined in the terms of the appended claims.

I claim:

1. In a crankshaft grinder, a support, a driven shaft carried by said support and having an outer end thereof projecting from said support, a cylindrical head of greater diameter than the shaft projecting from the outer end of the shaft and forming a mounting for a grinding wheel on the outer end of the shaft, said head formed with an annular recess in its lower surface which surrounds the shaft, and a tubular bushing encompassing the shaft with one end forming a bearing surface between the shaft and the support and the other end projecting into the annular recess in the head to form a bearing between the head and the shaft to eliminate lateral vibration on the outer end of the shaft.

2. In a crankshaft grinder, a cylindrical bonded abrasive wheel formed with a relatively broad, shallow recess in one axial end thereof, a driven grinding wheel drive shaft, a relatively broad, shallow member extending from one end of the shaft and adapted for mounting in the recess of said wheel, said member formed with an annular recess in its lower surface that surrounds the shaft within the limits of the wheel, and a tubular bushing surrounding the shaft and extending into the annular recess in said member and forming a lateral bearing surface between said member and the shaft which is partially within the interior of the wheel.

3. In a crankshaft grinder, a cylindrical bonded abrasive member formed with a relatively broad, shallow cylindrical recess in one axial end thereof, a driven shaft, a relatively broad, shallow cylindrical head united to one end of the shaft and adapted for mounting in the recess of the abrasive member, said head formed with an annular recess that surrounds the shaft within the limits of the abrasive member, a supporting member encompassing the shaft and spaced from the abrasive member, and a tubular bushing surrounding the shaft with one end extending into the annular recess in said abrasive member, and forming a lateral bearing surface between the head and one end of the shaft, and its other end extending into the supporting member and forming a bearing between the supporting member and the shaft to thereby support the shaft against lateral vibration.

References Cited in the file of this patent UNITED STATES PATENTS 416,518 Thibault Dec. 3, 1889 604,355 Keefe May 17, 1898 1,673,913 Iungensen June 19, 1928 1,967,744 Craft July 24, 1934 2,109,086 Coussement et al Feb. 22, 1938 2,149,258 Heitter Mar. 17, 1939 2,286,292 Mall June 16, 1942 2,324,377 Fischer July 13, 1943 

